A major goat of aging research is the generation of knowledge that will lead to the maintenance of functional independence in older populations. Sensory declines represent a broad category of normal age-related changes that can lead to diminished quality of life, loss of independence, and increased costs for society as a whole. Although progress has been made toward understanding the etiology and consequences of declines within individual sensory systems, there is a conspicuous lack of information concerning how aging influences the integration of information across sensory modalities. The study of multisensory integration is important for several reasons. First, it is of fundamental theoretical interest to understand the brain mechanisms that permit multisensory integration, as well as the functional behavioral significance of that integration. Second, understanding the processes of multisensory integration in older individuals may have great practical benefit, since one potentially fruitful approach to offsetting age-related declines in unisensory processing is to provide compensating information through other sensory channels. The specific aims of this one-year small-grant proposal are to pool the talents of a sensory psychophysicist and a specialist in the cognitive neuropsychology of aging to conduct and analyze the results of two experiments designed to measure the existence, magnitude and source mechanisms of multi.sensory interactions across the visual and auditory sensory domains; to compare and contrast the degree of multisensory integration in two disparate age groups: young adults (18-30 years) and older adults (60-75 years); and to use the preliminary data so obtained as the foundation for a subsequent R01 proposal to explore multisensory integration in older adults across a wider variety of sensory domains, and to critically examine and evaluate the feasibility of utilizing multisensory stimuli as a strategy to compensate for age-related declines in unisensory capacity.